     .banner_lb {
         width: 1000px;
         margin: 0 auto
     }

     div.mob_lb {
         width: 100%;
         margin: auto;
         position: relative;
     }

     div.mob_lb img {
         width: 100%;
         height: 360px;
         vertical-align: bottom;
     }

     .dote {
         position: absolute;
         bottom: 0;
         left: 0;
         right: 0;
         margin: auto;
         height: 20px;
         display: flex;
         justify-content: center;
         align-items: center;
     }

     .dote>span {
         display: inline-block;
         height: 10px;
         width: 10px;
         border-radius: 50%;
         margin: 2px;
     }

     span[class^="jian"] {
         position: absolute;

         margin-top: -50%;
         display: inline-block;
         height: 50px;
         width: 50px;
         border-radius: 80%;
         margin: 2px;
         background-color: rgba(0, 0, 0, 0.6);
         text-align: center;
         line-height: 50px;
         color: white;
         font-size: 24px;
         top: 0;
         bottom: 0;
         margin: auto;
     }

     .jianleft {
         left: 0;
     }

     .jianright {
         right: 0;
     }